1. Field of the Invention
The present invention relates to an apparatus and method for controlling the power of a personal computer (PC) system, and, more particularly, to an apparatus and method for controlling the power of a monitor, the monitor being automatically powered on and off according to the state of power of a PC, without the need to separately and manually power the monitor on and off.
2. Description of the Related Art
In order to reduce the power consumed in a PC monitor, the power supplied to the monitor should be controlled as disclosed in U.S. Pat. No. 5,880,719.
FIG. 1 shows a typical configuration of a PC system. As shown in FIG. 1, a PC system is typically comprised of a PC 100, a monitor 101, and a serial cable for data communications between the PC 100 and the monitor 101.
In order to operate the PC system, a power switch 100-1 for the PC 100 and a power switch 101-1 for the monitor 101 are switched on, respectively. When the PC 100 is powered on, a video card (not shown) within the PC 100 operates to output video signals. The output video signals are transmitted to the monitor 101 through the serial cable. After using the PC system, the power switches 100-1 and 101-1 are switched off to turn the PC 100 and the monitor 101 off, respectively.
As described above, it is inconvenient for a user to use the typical PC system since the PC 100 and the monitor 101 must be respectively powered on to operate the PC system, and respectively powered off after using the PC system. Further, in a case where the user forgets to power off the monitor 101 while powering off the PC 100, a problem occurs in that a significant amount of power is consumed by the monitor 101, which is continuously powered on.
FIG. 2 is a block diagram of a conventional apparatus for controlling the power of a monitor in a PC system. The PC system shown in FIG. 2 includes a PC 200, a monitor 201, and a serial cable for allowing data communication between the PC 200 and the monitor 201. The monitor 201 includes a power supply 201-1 for supplying power to other blocks within the monitor 201, a control unit 201-2 for sensing signals from the serial cable and generating a power switching control signal to control the power supplied to the other blocks within the monitor 201, and first, second, and third switches 201-3, 201-4, and 201-5 for switching the power supplied from the power supply 201-1 among the other blocks within the monitor 201 under the control of the control unit 201-2.
Signals output from the PC 200, i.e., VGA signals, are transmitted to the monitor 201 through the serial cable. The control unit 201-2 receives the signals output from the PC 200, and outputs a power switching control signal to control the power supplied to the other blocks within the monitor 201 according to the state of power of the PC 200. However, in order to monitor the state of the PC 200, a certain amount of power should be continuously supplied to the control unit 201-2. That is, even in a DPMS (Display Power Management System) mode, i.e., a power saving mode of the PC 200, a certain amount of power for driving at least the control unit 201-2 should be supplied to the monitor 201. Accordingly, unless the plug of the monitor 201 is pulled out, the monitor 201 is continuously powered on, and thus, power is continuously consumed.